I miss Fictionwise.
Sort by price, length, popularity, recent upload, author.
Download in several formats for non-DRMd books. (Which is all I would buy, but I don't care if other formats are carried--as long as they're clearly marked as DRM'd.)
I'd like the ability to download or view samples. Fictionwise's couple-hundred words was tolerable when they sold formerly-in-print books, but as soon as the self-pub market took off, it was inadequate. For print books, I can go to a store and flip through the book, read half a chapter if I like, to see if I like the writing style. I want the equivalent ability for ebooks.
Wishlist. SORTABLE wishlist. With subsections.
Lots of categories and subcategories. Ebooks aren't stored on shelves; you can put books "next to" each other by many types of tags.
Clear mention of publisher. (I'd hope that wouldn't need to be mentioned, but the EZReader bookstore didn't show that detail.)
I don't read DRM and I don't do wifi, so I have no stake in how or whether those features work. I just don't want them getting in the way.
Clear return policy--what happens if the store delivers the wrong file? If the ebook is corrupt, or has a cover but no text?
Customer service that responds to emails. As long as I'm talking fantasy features, how about customer service that's available by phone.
Ability to filter books out of search--either by genre/category, or format ("don't show me anything with DRM"), or by region, so non-US readers don't get halfway through a purchase before being told they can't buy that book.
Public domain texts clearly marked. Creative commons texts clearly marked. Let people know when they're allowed to play with the contents.
If the site uses Adobe DRM, clear instructions provided for that, not just "click here to visit Adobe's site and good luck figuring out how that works on your OS."
Ebooks listed by file format, not device. Or in addition to device.
Easily-findable sales/free ebooks.
No constantly-scrolling/changing images ANYWHERE unless they have an "off" button.